diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ef9ce5..3f67f24 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,10 +16,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Example SQL script in README file
 - Fixed misspelling
 
+### Changed
+- Support for Nextcloud 14 only
+- Group backend implementation
+- User backend implementation
+
 ### Fixed
 - Table and column autocomplete in settings panel
 
-## [v4.0.0-rc2] - 2018-06-14
+## [4.0.0-rc2] - 2018-06-14
 ### Added
 - User active column
 
@@ -79,6 +84,6 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Supported version of ownCloud, Nextcloud: ownCloud 10, Nextcloud 12
 
 [Unreleased]: https://github.com/nextcloud/user_sql/compare/v4.0.0-rc2...develop
-[v4.0.0-rc2]: https://github.com/nextcloud/user_sql/compare/v4.0.0-rc1...v4.0.0-rc2
+[4.0.0-rc2]: https://github.com/nextcloud/user_sql/compare/v4.0.0-rc1...v4.0.0-rc2
 [4.0.0-rc1]: https://github.com/nextcloud/user_sql/compare/v3.1.0...v4.0.0-rc1
 [3.1.0]: https://github.com/nextcloud/user_sql/compare/v2.4.0...v3.1.0
diff --git a/appinfo/info.xml b/appinfo/info.xml
index 0e5c94b..38207b0 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -10,8 +10,8 @@
     </description>
     <version>4.0.0-dev</version>
     <licence>agpl</licence>
-    <author>Andreas Böhler &lt;dev (at) aboehler (dot) at&gt;</author>
-    <author>Marcin Łojewski &lt;dev@mlojewski.me&gt;</author>
+    <author>Marcin Łojewski</author>
+    <author>Andreas Böhler</author>
     <namespace>UserSQL</namespace>
     <bugs>https://github.com/nextcloud/user_sql/issues</bugs>
     <repository>https://github.com/nextcloud/user_sql</repository>
@@ -22,7 +22,7 @@
     <category>auth</category>
     <dependencies>
         <php min-version="7.0"/>
-        <nextcloud min-version="13" max-version="13"/>
+        <nextcloud min-version="14" max-version="14"/>
     </dependencies>
     <settings>
         <admin>\OCA\UserSQL\Settings\Admin</admin>
diff --git a/lib/Backend/GroupBackend.php b/lib/Backend/GroupBackend.php
index 2ef5cd0..6174b26 100644
--- a/lib/Backend/GroupBackend.php
+++ b/lib/Backend/GroupBackend.php
@@ -21,12 +21,15 @@
 
 namespace OCA\UserSQL\Backend;
 
-use OC\Group\Backend;
 use OCA\UserSQL\Cache;
 use OCA\UserSQL\Constant\DB;
 use OCA\UserSQL\Model\Group;
 use OCA\UserSQL\Properties;
 use OCA\UserSQL\Repository\GroupRepository;
+use OCP\Group\Backend\ABackend;
+use OCP\Group\Backend\ICountUsersBackend;
+use OCP\Group\Backend\IGroupDetailsBackend;
+use OCP\Group\Backend\IIsAdminBackend;
 use OCP\ILogger;
 
 /**
@@ -34,7 +37,10 @@ use OCP\ILogger;
  *
  * @author Marcin Łojewski <dev@mlojewski.me>
  */
-final class GroupBackend extends Backend
+final class GroupBackend extends ABackend implements
+    ICountUsersBackend,
+    IGroupDetailsBackend,
+    IIsAdminBackend
 {
     /**
      * @var string The application name.
@@ -128,14 +134,9 @@ final class GroupBackend extends Backend
     }
 
     /**
-     * Returns the number of users in given group matching the search term.
-     *
-     * @param string $gid    The group ID.
-     * @param string $search The search term.
-     *
-     * @return int The number of users in given group matching the search term.
+     * @inheritdoc
      */
-    public function countUsersInGroup($gid, $search = "")
+    public function countUsersInGroup(string $gid, string $search = ""): int
     {
         $this->logger->debug(
             "Entering countUsersInGroup($gid, $search)",
@@ -355,18 +356,18 @@ final class GroupBackend extends Backend
     }
 
     /**
-     * Checks if a user is in the admin group.
-     *
-     * @param string $uid User ID.
-     *
-     * @return bool TRUE if a user is in the admin group, FALSE otherwise.
+     * @inheritdoc
      */
-    public function isAdmin($uid)
+    public function isAdmin(string $uid = null): bool
     {
         $this->logger->debug(
             "Entering isAdmin($uid)", ["app" => $this->appName]
         );
 
+        if (empty($this->properties[DB::GROUP_ADMIN_COLUMN]) || $uid === null) {
+            return false;
+        }
+
         $cacheKey = self::class . "admin_" . $uid;
         $admin = $this->cache->get($cacheKey);
 
@@ -394,18 +395,18 @@ final class GroupBackend extends Backend
     }
 
     /**
-     * Get associative array of the group details.
-     *
-     * @param string $gid The group ID.
-     *
-     * @return array Associative array of the group details.
+     * @inheritdoc
      */
-    public function getGroupDetails($gid)
+    public function getGroupDetails(string $gid): array
     {
         $this->logger->debug(
             "Entering getGroupDetails($gid)", ["app" => $this->appName]
         );
 
+        if (empty($this->properties[DB::GROUP_NAME_COLUMN])) {
+            return [];
+        }
+
         $group = $this->getGroup($gid);
 
         if (!($group instanceof Group)) {
@@ -421,21 +422,6 @@ final class GroupBackend extends Backend
         return $details;
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function getSupportedActions()
-    {
-        $actions = parent::getSupportedActions();
-
-        $actions &= empty($this->properties[DB::GROUP_ADMIN_COLUMN])
-            ? ~Backend::IS_ADMIN : ~0;
-        $actions &= empty($this->properties[DB::GROUP_NAME_COLUMN])
-            ? ~Backend::GROUP_DETAILS : ~0;
-
-        return $actions;
-    }
-
     /**
      * Check if this backend is correctly set and can be enabled.
      *
diff --git a/lib/Backend/UserBackend.php b/lib/Backend/UserBackend.php
index 442559e..a39b8fd 100644
--- a/lib/Backend/UserBackend.php
+++ b/lib/Backend/UserBackend.php
@@ -21,7 +21,6 @@
 
 namespace OCA\UserSQL\Backend;
 
-use OC\User\Backend;
 use OCA\UserSQL\Action\EmailSync;
 use OCA\UserSQL\Action\IUserAction;
 use OCA\UserSQL\Action\QuotaSync;
@@ -36,13 +35,28 @@ use OCA\UserSQL\Repository\UserRepository;
 use OCP\IConfig;
 use OCP\IL10N;
 use OCP\ILogger;
+use OCP\User\Backend\ABackend;
+use OCP\User\Backend\ICheckPasswordBackend;
+use OCP\User\Backend\ICountUsersBackend;
+use OCP\User\Backend\IGetDisplayNameBackend;
+use OCP\User\Backend\IGetHomeBackend;
+use OCP\User\Backend\IProvideAvatarBackend;
+use OCP\User\Backend\ISetDisplayNameBackend;
+use OCP\User\Backend\ISetPasswordBackend;
 
 /**
  * The SQL user backend manager.
  *
  * @author Marcin Łojewski <dev@mlojewski.me>
  */
-final class UserBackend extends Backend
+final class UserBackend extends ABackend implements
+    ICheckPasswordBackend,
+    ICountUsersBackend,
+    IGetDisplayNameBackend,
+    IGetHomeBackend,
+    IProvideAvatarBackend,
+    ISetDisplayNameBackend,
+    ISetPasswordBackend
 {
     /**
      * @var string The application name.
@@ -237,7 +251,7 @@ final class UserBackend extends Backend
     /**
      * @inheritdoc
      */
-    public function getDisplayName($uid)
+    public function getDisplayName($uid): string
     {
         $this->logger->debug(
             "Entering getDisplayName($uid)", ["app" => $this->appName]
@@ -267,7 +281,7 @@ final class UserBackend extends Backend
      *
      * @return string|bool The user ID on success, false otherwise.
      */
-    public function checkPassword($uid, $password)
+    public function checkPassword(string $uid, string $password)
     {
         $this->logger->debug(
             "Entering checkPassword($uid, *)", ["app" => $this->appName]
@@ -346,6 +360,10 @@ final class UserBackend extends Backend
             ["app" => $this->appName]
         );
 
+        if (empty($this->properties[DB::USER_NAME_COLUMN])) {
+            return false;
+        }
+
         $users = $this->getUsers($search, $limit, $offset);
 
         $names = [];
@@ -419,12 +437,16 @@ final class UserBackend extends Backend
      *
      * @return bool TRUE if the password has been set, FALSE otherwise.
      */
-    public function setPassword($uid, $password)
+    public function setPassword(string $uid, string $password): bool
     {
         $this->logger->debug(
             "Entering setPassword($uid, *)", ["app" => "user_sql"]
         );
 
+        if (empty($this->properties[Opt::PASSWORD_CHANGE])) {
+            return false;
+        }
+
         $passwordAlgorithm = $this->getPasswordAlgorithm();
         if ($passwordAlgorithm === false) {
             return false;
@@ -461,12 +483,16 @@ final class UserBackend extends Backend
     /**
      * @inheritdoc
      */
-    public function getHome($uid)
+    public function getHome(string $uid)
     {
         $this->logger->debug(
             "Entering getHome($uid)", ["app" => $this->appName]
         );
 
+        if (empty($this->properties[Opt::HOME_MODE])) {
+            return false;
+        }
+
         $home = false;
         switch ($this->properties[Opt::HOME_MODE]) {
         case App::HOME_STATIC:
@@ -496,12 +522,16 @@ final class UserBackend extends Backend
      *
      * @return bool TRUE if the user can change its avatar, FALSE otherwise.
      */
-    public function canChangeAvatar($uid)
+    public function canChangeAvatar(string $uid): bool
     {
         $this->logger->debug(
             "Entering canChangeAvatar($uid)", ["app" => $this->appName]
         );
 
+        if (empty($this->properties[DB::USER_AVATAR_COLUMN])) {
+            return false;
+        }
+
         $user = $this->userRepository->findByUid($uid);
         if (!($user instanceof User)) {
             return false;
@@ -524,13 +554,17 @@ final class UserBackend extends Backend
      *
      * @return bool TRUE if the password has been set, FALSE otherwise.
      */
-    public function setDisplayName($uid, $displayName)
+    public function setDisplayName(string $uid, string $displayName): bool
     {
         $this->logger->debug(
             "Entering setDisplayName($uid, $displayName)",
             ["app" => $this->appName]
         );
 
+        if (empty($this->properties[Opt::NAME_CHANGE])) {
+            return false;
+        }
+
         $user = $this->userRepository->findByUid($uid);
         if (!($user instanceof User)) {
             return false;
@@ -550,28 +584,6 @@ final class UserBackend extends Backend
         return false;
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function getSupportedActions()
-    {
-        $actions = parent::getSupportedActions();
-
-        $actions &= empty($this->properties[DB::USER_NAME_COLUMN])
-            ? ~Backend::GET_DISPLAYNAME : ~0;
-        $actions &= empty($this->properties[Opt::HOME_MODE])
-            ? ~Backend::GET_HOME : ~0;
-        $actions &= empty($this->properties[DB::USER_AVATAR_COLUMN])
-            ? ~Backend::PROVIDE_AVATAR : ~0;
-        $actions &= (!empty($this->properties[DB::USER_NAME_COLUMN])
-            && $this->properties[Opt::NAME_CHANGE]) ? ~0
-            : ~Backend::SET_DISPLAYNAME;
-        $actions &= $this->properties[Opt::PASSWORD_CHANGE] ? ~0
-            : ~Backend::SET_PASSWORD;
-
-        return $actions;
-    }
-
     /**
      * Check if this backend is correctly set and can be enabled.
      *
@@ -589,4 +601,20 @@ final class UserBackend extends Backend
             && !empty($this->properties[DB::USER_PASSWORD_COLUMN])
             && !empty($this->properties[Opt::CRYPTO_CLASS]);
     }
+
+    /**
+     * @inheritdoc
+     */
+    public function getBackendName()
+    {
+        return "User SQL";
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function deleteUser($uid)
+    {
+        return false;
+    }
 }
diff --git a/templates/admin.php b/templates/admin.php
index f64c847..7d2725f 100644
--- a/templates/admin.php
+++ b/templates/admin.php
@@ -21,8 +21,8 @@
 
 use OCP\IL10N;
 
-script('user_sql', 'settings');
-style('user_sql', 'settings');
+script("user_sql", "settings");
+style("user_sql", "settings");
 
 function print_text_input(IL10N $l, $id, $label, $value = "", $type = "text")
 {
@@ -71,6 +71,16 @@ function print_select_options(
         echo "</option>";
     }
 
+
+#54: Merge develop-14 into develop Conflicts
+Resolved all conflicts
+2 conflicting files
+CHANGELOG.md
+CHANGELOG.md
+admin.php
+templates/admin.php
+templates/admin.php
+Resolved
     echo "</select>";
     echo "</label></div>";
 }
@@ -94,11 +104,11 @@ function print_select_options(
             <p class="settings-hint"><?php p($l->t("Define your database connection parameters.")); ?></p>
             <fieldset><?php
                 $drivers = ["mysql" => "MySQL", "pgsql" => "PostgreSQL"];
-                print_select_options($l, "db-driver", "SQL driver", $drivers, $_['db.driver']);
-                print_text_input($l, "db-hostname", "Hostname", $_['db.hostname']);
-                print_text_input($l, "db-database", "Database", $_['db.database']);
-                print_text_input($l, "db-username", "Username", $_['db.username']);
-                print_text_input($l, "db-password", "Password", $_['db.password'], "password"); ?>
+                print_select_options($l, "db-driver", "SQL driver", $drivers, $_["db.driver"]);
+                print_text_input($l, "db-hostname", "Hostname", $_["db.hostname"]);
+                print_text_input($l, "db-database", "Database", $_["db.database"]);
+                print_text_input($l, "db-username", "Username", $_["db.username"]);
+                print_text_input($l, "db-password", "Password", $_["db.password"], "password"); ?>
                 <div class="button-right">
                     <input type="submit" id="user_sql-db_connection_verify" value="<?php p($l->t("Verify settings")); ?>">
                 </div>
@@ -108,16 +118,16 @@ function print_select_options(
             <h2><?php p($l->t("Options")); ?></h2>
             <p class="settings-hint"><?php p($l->t("Here are all currently supported options.")); ?></p>
             <fieldset><?php
-                print_checkbox_input($l, "opt-name_change", "Allow display name change", $_['opt.name_change']);
-                print_checkbox_input($l, "opt-password_change", "Allow password change", $_['opt.password_change']); ?>
+                print_checkbox_input($l, "opt-name_change", "Allow display name change", $_["opt.name_change"]);
+                print_checkbox_input($l, "opt-password_change", "Allow password change", $_["opt.password_change"]); ?>
                 <div class="button-right"><?php
-                    print_checkbox_input($l, "opt-use_cache", "Use cache", $_['opt.use_cache'], false); ?>
+                    print_checkbox_input($l, "opt-use_cache", "Use cache", $_["opt.use_cache"], false); ?>
                     <input type="submit" id="user_sql-clear_cache" value="<?php p($l->t("Clear cache")); ?>">
                 </div>
                 <?php
                 $hashes = [];
                 foreach (glob(__DIR__ . "/../lib/Crypto/*.php") as $filename) {
-                    $class = 'OCA\\UserSQL\\Crypto\\' . basename(substr($filename, 0, -4));
+                    $class = "OCA\\UserSQL\\Crypto\\" . basename(substr($filename, 0, -4));
                     try {
                         $passwordAlgorithm = new $class($l);
                         if ($passwordAlgorithm instanceof
@@ -129,58 +139,58 @@ function print_select_options(
                     }
                 }
 
-                print_select_options($l, "opt-crypto_class", "Hash algorithm", $hashes, $_['opt.crypto_class']);
-                print_select_options($l, "opt-email_sync", "Email sync", ["" => "None", "initial" => "Synchronise only once", "force_nc"=>"Nextcloud always wins", "force_sql"=>"SQL always wins"], $_['opt.email_sync']);
-                print_select_options($l, "opt-quota_sync", "Quota sync", ["" => "None", "initial" => "Synchronise only once", "force_nc"=>"Nextcloud always wins", "force_sql"=>"SQL always wins"], $_['opt.quota_sync']);
-                print_select_options($l, "opt-home_mode", "Home mode", ["" => "Default", "query" => "Query", "static" => "Static"], $_['opt.home_mode']);
-                print_text_input($l, "opt-home_location", "Home Location", $_['opt.home_location']); ?>
+                print_select_options($l, "opt-crypto_class", "Hash algorithm", $hashes, $_["opt.crypto_class"]);
+                print_select_options($l, "opt-email_sync", "Email sync", ["" => "None", "initial" => "Synchronise only once", "force_nc"=>"Nextcloud always wins", "force_sql"=>"SQL always wins"], $_["opt.email_sync"]);
+                print_select_options($l, "opt-quota_sync", "Quota sync", ["" => "None", "initial" => "Synchronise only once", "force_nc"=>"Nextcloud always wins", "force_sql"=>"SQL always wins"], $_["opt.quota_sync"]);
+                print_select_options($l, "opt-home_mode", "Home mode", ["" => "Default", "query" => "Query", "static" => "Static"], $_["opt.home_mode"]);
+                print_text_input($l, "opt-home_location", "Home Location", $_["opt.home_location"]); ?>
             </fieldset>
         </div>
         <div class="section clear-left">
             <h2><?php p($l->t("User table")); ?></h2>
             <p class="settings-hint"><?php p($l->t("Table containing user accounts.")); ?></p>
             <fieldset><?php
-                print_text_input($l, "db-table-user", "Table name", $_['db.table.user']) ;?>
+                print_text_input($l, "db-table-user", "Table name", $_["db.table.user"]); ?>
                 <h3><?php p($l->t("Columns")); ?></h3>
                 <?php
-                print_text_input($l, "db-table-user-column-uid", "Username", $_['db.table.user.column.uid']);
-                print_text_input($l, "db-table-user-column-email", "Email", $_['db.table.user.column.email']);
-                print_text_input($l, "db-table-user-column-quota", "Quota", $_['db.table.user.column.quota']);
-                print_text_input($l, "db-table-user-column-home", "Home", $_['db.table.user.column.home']);
-                print_text_input($l, "db-table-user-column-password", "Password", $_['db.table.user.column.password']);
-                print_text_input($l, "db-table-user-column-name", "Display name", $_['db.table.user.column.name']);
-                print_text_input($l, "db-table-user-column-active", "Active", $_['db.table.user.column.active']);
-                print_text_input($l, "db-table-user-column-avatar", "Provide avatar", $_['db.table.user.column.avatar']);
-                print_text_input($l, "db-table-user-column-salt", "Salt", $_['db.table.user.column.salt']); ?>
+                print_text_input($l, "db-table-user-column-uid", "Username", $_["db.table.user.column.uid"]);
+                print_text_input($l, "db-table-user-column-email", "Email", $_["db.table.user.column.email"]);
+                print_text_input($l, "db-table-user-column-quota", "Quota", $_["db.table.user.column.quota"]);
+                print_text_input($l, "db-table-user-column-home", "Home", $_["db.table.user.column.home"]);
+                print_text_input($l, "db-table-user-column-password", "Password", $_["db.table.user.column.password"]);
+                print_text_input($l, "db-table-user-column-name", "Display name", $_["db.table.user.column.name"]);
+                print_text_input($l, "db-table-user-column-active", "Active", $_["db.table.user.column.active"]);
+                print_text_input($l, "db-table-user-column-avatar", "Provide avatar", $_["db.table.user.column.avatar"]);
+                print_text_input($l, "db-table-user-column-salt", "Salt", $_["db.table.user.column.salt"]); ?>
             </fieldset>
         </div>
         <div class="section">
             <h2><?php p($l->t("Group table")); ?></h2>
             <p class="settings-hint"><?php p($l->t("Group definitions table.")); ?></p>
             <fieldset><?php
-                print_text_input($l, "db-table-group", "Table name", $_['db.table.group']); ?>
+                print_text_input($l, "db-table-group", "Table name", $_["db.table.group"]); ?>
                 <h3><?php p($l->t("Columns")); ?></h3>
                 <?php
-                print_text_input($l, "db-table-group-column-admin", "Is admin", $_['db.table.group.column.admin']);
-                print_text_input($l, "db-table-group-column-name", "Display name", $_['db.table.group.column.name']);
-                print_text_input($l, "db-table-group-column-gid", "Group name", $_['db.table.group.column.gid']); ?>
+                print_text_input($l, "db-table-group-column-admin", "Is admin", $_["db.table.group.column.admin"]);
+                print_text_input($l, "db-table-group-column-name", "Display name", $_["db.table.group.column.name"]);
+                print_text_input($l, "db-table-group-column-gid", "Group name", $_["db.table.group.column.gid"]); ?>
             </fieldset>
         </div>
         <div class="section">
             <h2><?php p($l->t("User group table")); ?></h2>
             <p class="settings-hint"><?php p($l->t("Associative table which maps users to groups.")); ?></p>
             <fieldset><?php
-                print_text_input($l, "db-table-user_group", "Table name", $_['db.table.user_group']); ?>
+                print_text_input($l, "db-table-user_group", "Table name", $_["db.table.user_group"]); ?>
                 <h3><?php p($l->t("Columns")); ?></h3>
                 <?php
-                print_text_input($l, "db-table-user_group-column-uid", "Username", $_['db.table.user_group.column.uid']);
-                print_text_input($l, "db-table-user_group-column-gid", "Group name", $_['db.table.user_group.column.gid']); ?>
+                print_text_input($l, "db-table-user_group-column-uid", "Username", $_["db.table.user_group.column.uid"]);
+                print_text_input($l, "db-table-user_group-column-gid", "Group name", $_["db.table.user_group.column.gid"]); ?>
             </fieldset>
         </div>
     </div>
     <div class="section">
         <input type="hidden" name="appname" value="user_sql"/>
-        <input type="hidden" name="requesttoken" value="<?php p($_['requesttoken']); ?>" id="requesttoken"/>
-        <input id="user_sql-save" type="submit" value="<?php p($l->t('Save')); ?>"/>
+        <input type="hidden" name="requesttoken" value="<?php p($_["requesttoken"]); ?>" id="requesttoken"/>
+        <input id="user_sql-save" type="submit" value="<?php p($l->t("Save")); ?>"/>
     </div>
 </form>